| 摘要 |
PROBLEM TO BE SOLVED: To determine a highly-accurate tire air pressure of each wheel inexpensively without using an air pressure sensor, in an electric vehicle wherein each wheel is driven by a separately independent electric motor. SOLUTION: A controller 50 operates: a slip angleβand vehicle speed V of an electric automatic four-wheeled vehicle; and a slip rate K<SB>i</SB>, an actual lateral force F<SB>Yi</SB>, cornering stiffness Ky (kf, kr), a grounding load F<SB>Z</SB>, and a cornering power Cp of each wheel, by using: each output from a steering angle sensor 111, a vehicle speed sensor 113, a yaw rate sensor 115, and an acceleration sensor 117; a value of height from a road surface to a point of the center of gravity of the electric automatic four-wheeled vehicle stored in a ROM 52, a value of an internal division ratio of a wheel base by the point of the center of gravity of the electric automatic four-wheeled vehicle, and tire data TD; and a given friction coefficientμof the road surface, and detects and estimates the tire air pressure Tp of each wheel by using correlation data in the ROM 52 from the cornering power Cp. COPYRIGHT: (C)2009,JPO&INPIT
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